Anti-angiogenic agents work by targeting the neovasculature of tumours, halting their growth, preventing tumour invasion, and precluding metastatic diffusion.20 Anti-angiogenic agents ideally should be used with other cancer therapies. More than one agent may be required to target different steps in the angiogenesis process.21
Angiogenesis inhibitors can have either a direct or indirect effect.10
- Direct anti-angiogenesis agents prevent vascular endothelial cells from proliferating, migrating, or avoiding cell death. They are not as likely to induce drug resistance.
- Indirect anti-angiogenesis agents prevent the expression of a tumour protein that activates angiogenesis or blocks the expression of its endothelial cell receptor.
Anti-angiogenesis agents that target the extracellular domain include bevacizumab. This therapy potently neutralises the biologic activities of human vascular endothelial growth factor (VEGF), preventing it from binding to VEGF receptor-2.
Anti-angiogenic agents that target the intracellular domain include sunitinib and sorafinib. These multi targeted tyrosine kinase inhibitors block the message in the endothelial cell that has been initiated by VEGFR-2. They have applications in renal cell carcinoma and GIST. Anti-angiogenic and immunomodulatory properties have also been identified in thalidomide. This drug is hypothesised to modulate VEGF inhibiting neovasculature. Another example of these agents is lenalidomide, although its exact mechanism is unknown.10
Identify an anti-angiogenic agent used in cancer treatment, and describe the:
- mechanism of action
- indications for its use in clinical practice
- nursing care considerations.
Discuss your response to a person who is concerned about being treated with thalidomide due to the drug's historical association with infant deformities.